diff options
Diffstat (limited to 'drivers/iio/adc/ad4695.c')
| -rw-r--r-- | drivers/iio/adc/ad4695.c | 2026 |
1 files changed, 2026 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad4695.c b/drivers/iio/adc/ad4695.c new file mode 100644 index 000000000000..cda419638d9a --- /dev/null +++ b/drivers/iio/adc/ad4695.c @@ -0,0 +1,2026 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * SPI ADC driver for Analog Devices Inc. AD4695 and similar chips + * + * https://www.analog.com/en/products/ad4695.html + * https://www.analog.com/en/products/ad4696.html + * https://www.analog.com/en/products/ad4697.html + * https://www.analog.com/en/products/ad4698.html + * + * Copyright 2024 Analog Devices Inc. + * Copyright 2024 BayLibre, SAS + */ + +#include <linux/align.h> +#include <linux/bitfield.h> +#include <linux/bits.h> +#include <linux/compiler.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/iio/buffer-dmaengine.h> +#include <linux/iio/buffer.h> +#include <linux/iio/iio.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/minmax.h> +#include <linux/mutex.h> +#include <linux/property.h> +#include <linux/pwm.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> +#include <linux/spi/offload/consumer.h> +#include <linux/spi/offload/provider.h> +#include <linux/spi/spi.h> +#include <linux/units.h> + +#include <dt-bindings/iio/adc/adi,ad4695.h> + +/* AD4695 registers */ +#define AD4695_REG_SPI_CONFIG_A 0x0000 +#define AD4695_REG_SPI_CONFIG_A_SW_RST (BIT(7) | BIT(0)) +#define AD4695_REG_SPI_CONFIG_A_ADDR_DIR BIT(5) +#define AD4695_REG_SPI_CONFIG_B 0x0001 +#define AD4695_REG_SPI_CONFIG_B_INST_MODE BIT(7) +#define AD4695_REG_DEVICE_TYPE 0x0003 +#define AD4695_REG_SCRATCH_PAD 0x000A +#define AD4695_REG_VENDOR_L 0x000C +#define AD4695_REG_VENDOR_H 0x000D +#define AD4695_REG_LOOP_MODE 0x000E +#define AD4695_REG_SPI_CONFIG_C 0x0010 +#define AD4695_REG_SPI_CONFIG_C_MB_STRICT BIT(7) +#define AD4695_REG_SPI_STATUS 0x0011 +#define AD4695_REG_STATUS 0x0014 +#define AD4695_REG_ALERT_STATUS1 0x0015 +#define AD4695_REG_ALERT_STATUS2 0x0016 +#define AD4695_REG_CLAMP_STATUS 0x001A +#define AD4695_REG_SETUP 0x0020 +#define AD4695_REG_SETUP_LDO_EN BIT(4) +#define AD4695_REG_SETUP_SPI_MODE BIT(2) +#define AD4695_REG_SETUP_SPI_CYC_CTRL BIT(1) +#define AD4695_REG_REF_CTRL 0x0021 +#define AD4695_REG_REF_CTRL_OV_MODE BIT(7) +#define AD4695_REG_REF_CTRL_VREF_SET GENMASK(4, 2) +#define AD4695_REG_REF_CTRL_REFHIZ_EN BIT(1) +#define AD4695_REG_REF_CTRL_REFBUF_EN BIT(0) +#define AD4695_REG_SEQ_CTRL 0x0022 +#define AD4695_REG_SEQ_CTRL_STD_SEQ_EN BIT(7) +#define AD4695_REG_SEQ_CTRL_NUM_SLOTS_AS GENMASK(6, 0) +#define AD4695_REG_AC_CTRL 0x0023 +#define AD4695_REG_STD_SEQ_CONFIG 0x0024 +#define AD4695_REG_GPIO_CTRL 0x0026 +#define AD4695_REG_GP_MODE 0x0027 +#define AD4695_REG_GP_MODE_BUSY_GP_SEL BIT(5) +#define AD4695_REG_GP_MODE_BUSY_GP_EN BIT(1) +#define AD4695_REG_TEMP_CTRL 0x0029 +#define AD4695_REG_TEMP_CTRL_TEMP_EN BIT(0) +#define AD4695_REG_CONFIG_IN(n) (0x0030 | (n)) +#define AD4695_REG_CONFIG_IN_MODE BIT(6) +#define AD4695_REG_CONFIG_IN_PAIR GENMASK(5, 4) +#define AD4695_REG_CONFIG_IN_AINHIGHZ_EN BIT(3) +#define AD4695_REG_CONFIG_IN_OSR_SET GENMASK(1, 0) +#define AD4695_REG_UPPER_IN(n) (0x0040 | (2 * (n))) +#define AD4695_REG_LOWER_IN(n) (0x0060 | (2 * (n))) +#define AD4695_REG_HYST_IN(n) (0x0080 | (2 * (n))) +#define AD4695_REG_OFFSET_IN(n) (0x00A0 | (2 * (n))) +#define AD4695_REG_GAIN_IN(n) (0x00C0 | (2 * (n))) +#define AD4695_REG_AS_SLOT(n) (0x0100 | (n)) +#define AD4695_REG_AS_SLOT_INX GENMASK(3, 0) + +/* Conversion mode commands */ +#define AD4695_CMD_EXIT_CNV_MODE 0x0A +#define AD4695_CMD_TEMP_CHAN 0x0F +#define AD4695_CMD_VOLTAGE_CHAN(n) (0x10 | (n)) + +/* timing specs */ +#define AD4695_T_CONVERT_NS 415 +#define AD4695_T_WAKEUP_HW_MS 3 +#define AD4695_T_WAKEUP_SW_MS 3 +#define AD4695_T_REFBUF_MS 100 +#define AD4695_T_REGCONFIG_NS 20 +#define AD4695_T_SCK_CNV_DELAY_NS 80 +#define AD4695_T_CNVL_NS 80 +#define AD4695_T_CNVH_NS 10 +#define AD4695_REG_ACCESS_SCLK_HZ (10 * MEGA) + +/* Max number of voltage input channels. */ +#define AD4695_MAX_VIN_CHANNELS 16 + +enum ad4695_in_pair { + AD4695_IN_PAIR_REFGND, + AD4695_IN_PAIR_COM, + AD4695_IN_PAIR_EVEN_ODD, +}; + +struct ad4695_chip_info { + const char *name; + int max_sample_rate; + u32 t_acq_ns; + u8 num_voltage_inputs; +}; + +struct ad4695_channel_config { + unsigned int channel; + bool highz_en; + bool bipolar; + enum ad4695_in_pair pin_pairing; + unsigned int common_mode_mv; + unsigned int oversampling_ratio; +}; + +struct ad4695_state { + struct spi_device *spi; + struct spi_offload *offload; + struct spi_offload_trigger *offload_trigger; + struct regmap *regmap; + struct regmap *regmap16; + struct gpio_desc *reset_gpio; + /* currently PWM CNV only supported with SPI offload use */ + struct pwm_device *cnv_pwm; + /* protects against concurrent use of cnv_pwm */ + struct mutex cnv_pwm_lock; + /* offload also requires separate gpio to manually control CNV */ + struct gpio_desc *cnv_gpio; + /* voltages channels plus temperature and timestamp */ + struct iio_chan_spec iio_chan[AD4695_MAX_VIN_CHANNELS + 2]; + struct ad4695_channel_config channels_cfg[AD4695_MAX_VIN_CHANNELS]; + const struct ad4695_chip_info *chip_info; + int sample_freq_range[3]; + /* Reference voltage. */ + unsigned int vref_mv; + /* Common mode input pin voltage. */ + unsigned int com_mv; + /* + * 2 per voltage and temperature chan plus 1 xfer to trigger 1st + * CNV. Excluding the trigger xfer, every 2nd xfer only serves + * to control CS and add a delay between the last SCLK and next + * CNV rising edges. + */ + struct spi_transfer buf_read_xfer[AD4695_MAX_VIN_CHANNELS * 2 + 3]; + struct spi_message buf_read_msg; + /* Raw conversion data received. */ + IIO_DECLARE_DMA_BUFFER_WITH_TS(u16, buf, AD4695_MAX_VIN_CHANNELS + 1); + u16 raw_data; + /* Commands to send for single conversion. */ + u16 cnv_cmd; + u8 cnv_cmd2; + /* Buffer for storing data from regmap bus reads/writes */ + u8 regmap_bus_data[4]; +}; + +static const struct regmap_range ad4695_regmap_rd_ranges[] = { + regmap_reg_range(AD4695_REG_SPI_CONFIG_A, AD4695_REG_SPI_CONFIG_B), + regmap_reg_range(AD4695_REG_DEVICE_TYPE, AD4695_REG_DEVICE_TYPE), + regmap_reg_range(AD4695_REG_SCRATCH_PAD, AD4695_REG_SCRATCH_PAD), + regmap_reg_range(AD4695_REG_VENDOR_L, AD4695_REG_LOOP_MODE), + regmap_reg_range(AD4695_REG_SPI_CONFIG_C, AD4695_REG_SPI_STATUS), + regmap_reg_range(AD4695_REG_STATUS, AD4695_REG_ALERT_STATUS2), + regmap_reg_range(AD4695_REG_CLAMP_STATUS, AD4695_REG_CLAMP_STATUS), + regmap_reg_range(AD4695_REG_SETUP, AD4695_REG_AC_CTRL), + regmap_reg_range(AD4695_REG_GPIO_CTRL, AD4695_REG_TEMP_CTRL), + regmap_reg_range(AD4695_REG_CONFIG_IN(0), AD4695_REG_CONFIG_IN(15)), + regmap_reg_range(AD4695_REG_AS_SLOT(0), AD4695_REG_AS_SLOT(127)), +}; + +static const struct regmap_access_table ad4695_regmap_rd_table = { + .yes_ranges = ad4695_regmap_rd_ranges, + .n_yes_ranges = ARRAY_SIZE(ad4695_regmap_rd_ranges), +}; + +static const struct regmap_range ad4695_regmap_wr_ranges[] = { + regmap_reg_range(AD4695_REG_SPI_CONFIG_A, AD4695_REG_SPI_CONFIG_B), + regmap_reg_range(AD4695_REG_SCRATCH_PAD, AD4695_REG_SCRATCH_PAD), + regmap_reg_range(AD4695_REG_LOOP_MODE, AD4695_REG_LOOP_MODE), + regmap_reg_range(AD4695_REG_SPI_CONFIG_C, AD4695_REG_SPI_STATUS), + regmap_reg_range(AD4695_REG_SETUP, AD4695_REG_AC_CTRL), + regmap_reg_range(AD4695_REG_GPIO_CTRL, AD4695_REG_TEMP_CTRL), + regmap_reg_range(AD4695_REG_CONFIG_IN(0), AD4695_REG_CONFIG_IN(15)), + regmap_reg_range(AD4695_REG_AS_SLOT(0), AD4695_REG_AS_SLOT(127)), +}; + +static const struct regmap_access_table ad4695_regmap_wr_table = { + .yes_ranges = ad4695_regmap_wr_ranges, + .n_yes_ranges = ARRAY_SIZE(ad4695_regmap_wr_ranges), +}; + +static const struct regmap_config ad4695_regmap_config = { + .name = "ad4695-8", + .reg_bits = 16, + .val_bits = 8, + .max_register = AD4695_REG_AS_SLOT(127), + .rd_table = &ad4695_regmap_rd_table, + .wr_table = &ad4695_regmap_wr_table, +}; + +static const struct regmap_range ad4695_regmap16_rd_ranges[] = { + regmap_reg_range(AD4695_REG_STD_SEQ_CONFIG, AD4695_REG_STD_SEQ_CONFIG), + regmap_reg_range(AD4695_REG_UPPER_IN(0), AD4695_REG_GAIN_IN(15)), +}; + +static const struct regmap_access_table ad4695_regmap16_rd_table = { + .yes_ranges = ad4695_regmap16_rd_ranges, + .n_yes_ranges = ARRAY_SIZE(ad4695_regmap16_rd_ranges), +}; + +static const struct regmap_range ad4695_regmap16_wr_ranges[] = { + regmap_reg_range(AD4695_REG_STD_SEQ_CONFIG, AD4695_REG_STD_SEQ_CONFIG), + regmap_reg_range(AD4695_REG_UPPER_IN(0), AD4695_REG_GAIN_IN(15)), +}; + +static const struct regmap_access_table ad4695_regmap16_wr_table = { + .yes_ranges = ad4695_regmap16_wr_ranges, + .n_yes_ranges = ARRAY_SIZE(ad4695_regmap16_wr_ranges), +}; + +static const struct regmap_config ad4695_regmap16_config = { + .name = "ad4695-16", + .reg_bits = 16, + .reg_stride = 2, + .val_bits = 16, + .val_format_endian = REGMAP_ENDIAN_LITTLE, + .max_register = AD4695_REG_GAIN_IN(15), + .rd_table = &ad4695_regmap16_rd_table, + .wr_table = &ad4695_regmap16_wr_table, +}; + +static int ad4695_regmap_bus_reg_write(void *context, const void *data, + size_t count) +{ + struct ad4695_state *st = context; + struct spi_transfer xfer = { + .speed_hz = AD4695_REG_ACCESS_SCLK_HZ, + .len = count, + .tx_buf = st->regmap_bus_data, + }; + + if (count > ARRAY_SIZE(st->regmap_bus_data)) + return -EINVAL; + + memcpy(st->regmap_bus_data, data, count); + + return spi_sync_transfer(st->spi, &xfer, 1); +} + +static int ad4695_regmap_bus_reg_read(void *context, const void *reg, + size_t reg_size, void *val, + size_t val_size) +{ + struct ad4695_state *st = context; + struct spi_transfer xfers[] = { + { + .speed_hz = AD4695_REG_ACCESS_SCLK_HZ, + .len = reg_size, + .tx_buf = &st->regmap_bus_data[0], + }, { + .speed_hz = AD4695_REG_ACCESS_SCLK_HZ, + .len = val_size, + .rx_buf = &st->regmap_bus_data[2], + }, + }; + int ret; + + if (reg_size > 2) + return -EINVAL; + + if (val_size > 2) + return -EINVAL; + + memcpy(&st->regmap_bus_data[0], reg, reg_size); + + ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers)); + if (ret) + return ret; + + memcpy(val, &st->regmap_bus_data[2], val_size); + + return 0; +} + +static const struct regmap_bus ad4695_regmap_bus = { + .write = ad4695_regmap_bus_reg_write, + .read = ad4695_regmap_bus_reg_read, + .read_flag_mask = 0x80, + .reg_format_endian_default = REGMAP_ENDIAN_BIG, + .val_format_endian_default = REGMAP_ENDIAN_BIG, +}; + +enum { + AD4695_SCAN_TYPE_OSR_1, + AD4695_SCAN_TYPE_OSR_4, + AD4695_SCAN_TYPE_OSR_16, + AD4695_SCAN_TYPE_OSR_64, +}; + +static const struct iio_scan_type ad4695_scan_type_offload_u[] = { + [AD4695_SCAN_TYPE_OSR_1] = { + .sign = 'u', + .realbits = 16, + .shift = 3, + .storagebits = 32, + }, + [AD4695_SCAN_TYPE_OSR_4] = { + .sign = 'u', + .realbits = 17, + .shift = 2, + .storagebits = 32, + }, + [AD4695_SCAN_TYPE_OSR_16] = { + .sign = 'u', + .realbits = 18, + .shift = 1, + .storagebits = 32, + }, + [AD4695_SCAN_TYPE_OSR_64] = { + .sign = 'u', + .realbits = 19, + .storagebits = 32, + }, +}; + +static const struct iio_scan_type ad4695_scan_type_offload_s[] = { + [AD4695_SCAN_TYPE_OSR_1] = { + .sign = 's', + .realbits = 16, + .shift = 3, + .storagebits = 32, + }, + [AD4695_SCAN_TYPE_OSR_4] = { + .sign = 's', + .realbits = 17, + .shift = 2, + .storagebits = 32, + }, + [AD4695_SCAN_TYPE_OSR_16] = { + .sign = 's', + .realbits = 18, + .shift = 1, + .storagebits = 32, + }, + [AD4695_SCAN_TYPE_OSR_64] = { + .sign = 's', + .realbits = 19, + .storagebits = 32, + }, +}; + +static const struct iio_chan_spec ad4695_channel_template = { + .type = IIO_VOLTAGE, + .indexed = 1, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_OFFSET) | + BIT(IIO_CHAN_INFO_CALIBSCALE) | + BIT(IIO_CHAN_INFO_CALIBBIAS), + .info_mask_separate_available = BIT(IIO_CHAN_INFO_CALIBSCALE) | + BIT(IIO_CHAN_INFO_CALIBBIAS), + .scan_type = { + .sign = 'u', + .realbits = 16, + .storagebits = 16, + }, +}; + +static const struct iio_chan_spec ad4695_temp_channel_template = { + .address = AD4695_CMD_TEMP_CHAN, + .type = IIO_TEMP, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_OFFSET), + .scan_type = { + .sign = 's', + .realbits = 16, + .storagebits = 16, + }, +}; + +static const struct iio_chan_spec ad4695_soft_timestamp_channel_template = + IIO_CHAN_SOFT_TIMESTAMP(0); + +static const char * const ad4695_power_supplies[] = { + "avdd", "vio" +}; + +static const int ad4695_oversampling_ratios[] = { + 1, 4, 16, 64, +}; + +static const struct ad4695_chip_info ad4695_chip_info = { + .name = "ad4695", + .max_sample_rate = 500 * KILO, + .t_acq_ns = 1715, + .num_voltage_inputs = 16, +}; + +static const struct ad4695_chip_info ad4696_chip_info = { + .name = "ad4696", + .max_sample_rate = 1 * MEGA, + .t_acq_ns = 715, + .num_voltage_inputs = 16, +}; + +static const struct ad4695_chip_info ad4697_chip_info = { + .name = "ad4697", + .max_sample_rate = 500 * KILO, + .t_acq_ns = 1715, + .num_voltage_inputs = 8, +}; + +static const struct ad4695_chip_info ad4698_chip_info = { + .name = "ad4698", + .max_sample_rate = 1 * MEGA, + .t_acq_ns = 715, + .num_voltage_inputs = 8, +}; + +static void ad4695_cnv_manual_trigger(struct ad4695_state *st) +{ + gpiod_set_value_cansleep(st->cnv_gpio, 1); + ndelay(10); + gpiod_set_value_cansleep(st->cnv_gpio, 0); +} + +/** + * ad4695_set_single_cycle_mode - Set the device in single cycle mode + * @st: The AD4695 state + * @channel: The first channel to read + * + * As per the datasheet, to enable single cycle mode, we need to set + * STD_SEQ_EN=0, NUM_SLOTS_AS=0 and CYC_CTRL=1 (Table 15). Setting SPI_MODE=1 + * triggers the first conversion using the channel in AS_SLOT0. + * + * Context: can sleep, must be called with iio_device_claim_direct held + * Return: 0 on success, a negative error code on failure + */ +static int ad4695_set_single_cycle_mode(struct ad4695_state *st, + unsigned int channel) +{ + int ret; + + ret = regmap_clear_bits(st->regmap, AD4695_REG_SEQ_CTRL, + AD4695_REG_SEQ_CTRL_STD_SEQ_EN | + AD4695_REG_SEQ_CTRL_NUM_SLOTS_AS); + if (ret) + return ret; + + ret = regmap_write(st->regmap, AD4695_REG_AS_SLOT(0), + FIELD_PREP(AD4695_REG_AS_SLOT_INX, channel)); + if (ret) + return ret; + + return regmap_set_bits(st->regmap, AD4695_REG_SETUP, + AD4695_REG_SETUP_SPI_MODE | + AD4695_REG_SETUP_SPI_CYC_CTRL); +} + +/** + * ad4695_enter_advanced_sequencer_mode - Put the ADC in advanced sequencer mode + * @st: The driver state + * @n: The number of slots to use - must be >= 2, <= 128 + * + * As per the datasheet, to enable advanced sequencer, we need to set + * STD_SEQ_EN=0, NUM_SLOTS_AS=n-1 and CYC_CTRL=0 (Table 15). Setting SPI_MODE=1 + * triggers the first conversion using the channel in AS_SLOT0. + * + * Return: 0 on success, a negative error code on failure + */ +static int ad4695_enter_advanced_sequencer_mode(struct ad4695_state *st, u32 n) +{ + int ret; + + ret = regmap_update_bits(st->regmap, AD4695_REG_SEQ_CTRL, + AD4695_REG_SEQ_CTRL_STD_SEQ_EN | + AD4695_REG_SEQ_CTRL_NUM_SLOTS_AS, + FIELD_PREP(AD4695_REG_SEQ_CTRL_STD_SEQ_EN, 0) | + FIELD_PREP(AD4695_REG_SEQ_CTRL_NUM_SLOTS_AS, n - 1)); + if (ret) + return ret; + + return regmap_update_bits(st->regmap, AD4695_REG_SETUP, + AD4695_REG_SETUP_SPI_MODE | AD4695_REG_SETUP_SPI_CYC_CTRL, + FIELD_PREP(AD4695_REG_SETUP_SPI_MODE, 1) | + FIELD_PREP(AD4695_REG_SETUP_SPI_CYC_CTRL, 0)); +} + +/** + * ad4695_exit_conversion_mode - Exit conversion mode + * @st: The AD4695 state + * + * Sends SPI command to exit conversion mode. + * + * Return: 0 on success, a negative error code on failure + */ +static int ad4695_exit_conversion_mode(struct ad4695_state *st) +{ + /* + * An extra transfer is needed to trigger a conversion here so + * that we can be 100% sure the command will be processed by the + * ADC, rather than relying on it to be in the correct state + * when this function is called (this chip has a quirk where the + * command only works when reading a conversion, and if the + * previous conversion was already read then it won't work). The + * actual conversion command is then run at the slower + * AD4695_REG_ACCESS_SCLK_HZ speed to guarantee this works. + */ + struct spi_transfer xfers[] = { + { + .delay.value = AD4695_T_CNVL_NS, + .delay.unit = SPI_DELAY_UNIT_NSECS, + .cs_change = 1, + .cs_change_delay.value = AD4695_T_CNVH_NS, + .cs_change_delay.unit = SPI_DELAY_UNIT_NSECS, + }, + { + .speed_hz = AD4695_REG_ACCESS_SCLK_HZ, + .tx_buf = &st->cnv_cmd2, + .len = 1, + .delay.value = AD4695_T_REGCONFIG_NS, + .delay.unit = SPI_DELAY_UNIT_NSECS, + }, + }; + + /* + * Technically, could do a 5-bit transfer, but shifting to start of + * 8 bits instead for better SPI controller support. + */ + st->cnv_cmd2 = AD4695_CMD_EXIT_CNV_MODE << 3; + + if (st->cnv_gpio) { + ad4695_cnv_manual_trigger(st); + + /* + * In this case, CNV is not connected to CS, so we don't need + * the extra CS toggle to trigger the conversion and toggling + * CS would have no effect. + */ + return spi_sync_transfer(st->spi, &xfers[1], 1); + } + + return spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers)); +} + +static int ad4695_set_ref_voltage(struct ad4695_state *st, int vref_mv) +{ + u8 val; + + if (vref_mv >= 2400 && vref_mv <= 2750) + val = 0; + else if (vref_mv > 2750 && vref_mv <= 3250) + val = 1; + else if (vref_mv > 3250 && vref_mv <= 3750) + val = 2; + else if (vref_mv > 3750 && vref_mv <= 4500) + val = 3; + else if (vref_mv > 4500 && vref_mv <= 5100) + val = 4; + else + return -EINVAL; + + return regmap_update_bits(st->regmap, AD4695_REG_REF_CTRL, + AD4695_REG_REF_CTRL_VREF_SET, + FIELD_PREP(AD4695_REG_REF_CTRL_VREF_SET, val)); +} + +/** + * ad4695_osr_to_regval - convert ratio to OSR register value + * @ratio: ratio to check + * + * Check if ratio is present in the list of available ratios and return + * the corresponding value that needs to be written to the register to + * select that ratio. + * + * Returns: register value (0 to 3) or -EINVAL if there is not an exact + * match + */ +static int ad4695_osr_to_regval(int ratio) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(ad4695_oversampling_ratios); i++) { + if (ratio == ad4695_oversampling_ratios[i]) + return i; + } + + return -EINVAL; +} + +static int ad4695_write_chn_cfg(struct ad4695_state *st, + struct ad4695_channel_config *cfg) +{ + u32 mask, val; + + mask = AD4695_REG_CONFIG_IN_MODE; + val = FIELD_PREP(AD4695_REG_CONFIG_IN_MODE, cfg->bipolar ? 1 : 0); + + mask |= AD4695_REG_CONFIG_IN_PAIR; + val |= FIELD_PREP(AD4695_REG_CONFIG_IN_PAIR, cfg->pin_pairing); + + mask |= AD4695_REG_CONFIG_IN_AINHIGHZ_EN; + val |= FIELD_PREP(AD4695_REG_CONFIG_IN_AINHIGHZ_EN, + cfg->highz_en ? 1 : 0); + + return regmap_update_bits(st->regmap, + AD4695_REG_CONFIG_IN(cfg->channel), + mask, val); +} + +static int ad4695_buffer_preenable(struct iio_dev *indio_dev) +{ + struct ad4695_state *st = iio_priv(indio_dev); + struct spi_transfer *xfer; + u8 temp_chan_bit = st->chip_info->num_voltage_inputs; + u32 bit, num_xfer, num_slots; + u32 temp_en = 0; + int ret, rx_buf_offset = 0; + + /* + * We are using the advanced sequencer since it is the only way to read + * multiple channels that allows individual configuration of each + * voltage input channel. Slot 0 in the advanced sequencer is used to + * account for the gap between trigger polls - we don't read data from + * this slot. Each enabled voltage channel is assigned a slot starting + * with slot 1. + */ + num_slots = 1; + + memset(st->buf_read_xfer, 0, sizeof(st->buf_read_xfer)); + + /* First xfer is only to trigger conversion of slot 1, so no rx. */ + xfer = &st->buf_read_xfer[0]; + xfer->cs_change = 1; + xfer->delay.value = st->chip_info->t_acq_ns; + xfer->delay.unit = SPI_DELAY_UNIT_NSECS; + xfer->cs_change_delay.value = AD4695_T_CONVERT_NS; + xfer->cs_change_delay.unit = SPI_DELAY_UNIT_NSECS; + num_xfer = 1; + + iio_for_each_active_channel(indio_dev, bit) { + xfer = &st->buf_read_xfer[num_xfer]; + xfer->bits_per_word = 16; + xfer->rx_buf = &st->buf[rx_buf_offset++]; + xfer->len = 2; + + if (bit == temp_chan_bit) { + temp_en = 1; + } else { + ret = regmap_write(st->regmap, + AD4695_REG_AS_SLOT(num_slots), + FIELD_PREP(AD4695_REG_AS_SLOT_INX, bit)); + if (ret) + return ret; + + num_slots++; + } + + num_xfer++; + + /* + * We need to add a blank xfer in data reads, to meet the timing + * requirement of a minimum delay between the last SCLK rising + * edge and the CS deassert. + */ + xfer = &st->buf_read_xfer[num_xfer]; + xfer->delay.value = AD4695_T_SCK_CNV_DELAY_NS; + xfer->delay.unit = SPI_DELAY_UNIT_NSECS; + xfer->cs_change = 1; + xfer->cs_change_delay.value = AD4695_T_CONVERT_NS; + xfer->cs_change_delay.unit = SPI_DELAY_UNIT_NSECS; + + num_xfer++; + } + + /* + * The advanced sequencer requires that at least 2 slots are enabled. + * Since slot 0 is always used for other purposes, we need only 1 + * enabled voltage channel to meet this requirement. If the temperature + * channel is the only enabled channel, we need to add one more slot in + * the sequence but not read from it. This is because the temperature + * sensor is sampled at the end of the channel sequence in advanced + * sequencer mode (see datasheet page 38). + * + * From the iio_for_each_active_channel() block above, we now have an + * xfer with data followed by a blank xfer to allow us to meet the + * timing spec, so move both of those up before adding an extra to + * handle the temperature-only case. + */ + if (num_slots < 2) { + /* Move last two xfers */ + st->buf_read_xfer[num_xfer] = st->buf_read_xfer[num_xfer - 1]; + st->buf_read_xfer[num_xfer - 1] = st->buf_read_xfer[num_xfer - 2]; + num_xfer++; + + /* Modify inserted xfer for extra slot. */ + xfer = &st->buf_read_xfer[num_xfer - 3]; + memset(xfer, 0, sizeof(*xfer)); + xfer->cs_change = 1; + xfer->delay.value = st->chip_info->t_acq_ns; + xfer->delay.unit = SPI_DELAY_UNIT_NSECS; + xfer->cs_change_delay.value = AD4695_T_CONVERT_NS; + xfer->cs_change_delay.unit = SPI_DELAY_UNIT_NSECS; + xfer++; + + /* and add the extra slot in the sequencer */ + ret = regmap_write(st->regmap, + AD4695_REG_AS_SLOT(num_slots), + FIELD_PREP(AD4695_REG_AS_SLOT_INX, 0)); + if (ret) + return ret; + + num_slots++; + + /* + * We still want to point at the last xfer when finished, so + * update the pointer. + */ + xfer = &st->buf_read_xfer[num_xfer - 1]; + } + + /* + * Don't keep CS asserted after last xfer. Also triggers conversion of + * slot 0. + */ + xfer->cs_change = 0; + + /* + * Temperature channel isn't included in the sequence, but rather + * controlled by setting a bit in the TEMP_CTRL register. + */ + + ret = regmap_update_bits(st->regmap, AD4695_REG_TEMP_CTRL, + AD4695_REG_TEMP_CTRL_TEMP_EN, + FIELD_PREP(AD4695_REG_TEMP_CTRL_TEMP_EN, temp_en)); + if (ret) + return ret; + + spi_message_init_with_transfers(&st->buf_read_msg, st->buf_read_xfer, + num_xfer); + + ret = spi_optimize_message(st->spi, &st->buf_read_msg); + if (ret) + return ret; + + /* This triggers conversion of slot 0. */ + ret = ad4695_enter_advanced_sequencer_mode(st, num_slots); + if (ret) + spi_unoptimize_message(&st->buf_read_msg); + + return ret; +} + +static int ad4695_buffer_postdisable(struct iio_dev *indio_dev) +{ + struct ad4695_state *st = iio_priv(indio_dev); + int ret; + + ret = ad4695_exit_conversion_mode(st); + if (ret) + return ret; + + spi_unoptimize_message(&st->buf_read_msg); + + return 0; +} + +static const struct iio_buffer_setup_ops ad4695_buffer_setup_ops = { + .preenable = ad4695_buffer_preenable, + .postdisable = ad4695_buffer_postdisable, +}; + +static irqreturn_t ad4695_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct ad4695_state *st = iio_priv(indio_dev); + int ret; + + ret = spi_sync(st->spi, &st->buf_read_msg); + if (ret) + goto out; + + iio_push_to_buffers_with_ts(indio_dev, st->buf, sizeof(st->buf), + pf->timestamp); + +out: + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + +static int ad4695_offload_buffer_postenable(struct iio_dev *indio_dev) +{ + struct ad4695_state *st = iio_priv(indio_dev); + struct spi_offload_trigger_config config = { + .type = SPI_OFFLOAD_TRIGGER_DATA_READY, + }; + struct spi_transfer *xfer = &st->buf_read_xfer[0]; + struct pwm_state state; + u8 temp_chan_bit = st->chip_info->num_voltage_inputs; + u8 num_slots = 0; + u8 temp_en = 0; + unsigned int bit; + int ret; + + iio_for_each_active_channel(indio_dev, bit) { + if (bit == temp_chan_bit) { + temp_en = 1; + continue; + } + + ret = regmap_write(st->regmap, AD4695_REG_AS_SLOT(num_slots), + FIELD_PREP(AD4695_REG_AS_SLOT_INX, bit)); + if (ret) + return ret; + + num_slots++; + } + + /* + * For non-offload, we could discard data to work around this + * restriction, but with offload, that is not possible. + */ + if (num_slots < 2) { + dev_err(&st->spi->dev, + "At least two voltage channels must be enabled.\n"); + return -EINVAL; + } + + ret = regmap_update_bits(st->regmap, AD4695_REG_TEMP_CTRL, + AD4695_REG_TEMP_CTRL_TEMP_EN, + FIELD_PREP(AD4695_REG_TEMP_CTRL_TEMP_EN, + temp_en)); + if (ret) + return ret; + + /* Each BUSY event means just one sample for one channel is ready. */ + memset(xfer, 0, sizeof(*xfer)); + xfer->offload_flags = SPI_OFFLOAD_XFER_RX_STREAM; + /* Using 19 bits per word to allow for possible oversampling */ + xfer->bits_per_word = 19; + xfer->len = 4; + + spi_message_init_with_transfers(&st->buf_read_msg, xfer, 1); + st->buf_read_msg.offload = st->offload; + + ret = spi_optimize_message(st->spi, &st->buf_read_msg); + if (ret) + return ret; + + /* + * NB: technically, this is part the SPI offload trigger enable, but it + * doesn't work to call it from the offload trigger enable callback + * because it requires accessing the SPI bus. Calling it from the + * trigger enable callback could cause a deadlock. + */ + ret = regmap_set_bits(st->regmap, AD4695_REG_GP_MODE, + AD4695_REG_GP_MODE_BUSY_GP_EN); + if (ret) + goto err_unoptimize_message; + + ret = spi_offload_trigger_enable(st->offload, st->offload_trigger, + &config); + if (ret) + goto err_disable_busy_output; + + ret = ad4695_enter_advanced_sequencer_mode(st, num_slots); + if (ret) + goto err_offload_trigger_disable; + + mutex_lock(&st->cnv_pwm_lock); + pwm_get_state(st->cnv_pwm, &state); + /* + * PWM subsystem generally rounds down, so requesting 2x minimum high + * time ensures that we meet the minimum high time in any case. + */ + state.duty_cycle = AD4695_T_CNVH_NS * 2; + ret = pwm_apply_might_sleep(st->cnv_pwm, &state); + mutex_unlock(&st->cnv_pwm_lock); + if (ret) + goto err_offload_exit_conversion_mode; + + return 0; + +err_offload_exit_conversion_mode: + /* + * We have to unwind in a different order to avoid triggering offload. + * ad4695_exit_conversion_mode() triggers a conversion, so it has to be + * done after spi_offload_trigger_disable(). + */ + spi_offload_trigger_disable(st->offload, st->offload_trigger); + ad4695_exit_conversion_mode(st); + goto err_disable_busy_output; + +err_offload_trigger_disable: + spi_offload_trigger_disable(st->offload, st->offload_trigger); + +err_disable_busy_output: + regmap_clear_bits(st->regmap, AD4695_REG_GP_MODE, + AD4695_REG_GP_MODE_BUSY_GP_EN); + +err_unoptimize_message: + spi_unoptimize_message(&st->buf_read_msg); + + return ret; +} + +static int ad4695_offload_buffer_predisable(struct iio_dev *indio_dev) +{ + struct ad4695_state *st = iio_priv(indio_dev); + struct pwm_state state; + int ret; + + scoped_guard(mutex, &st->cnv_pwm_lock) { + pwm_get_state(st->cnv_pwm, &state); + state.duty_cycle = 0; + ret = pwm_apply_might_sleep(st->cnv_pwm, &state); + if (ret) + return ret; + } + + spi_offload_trigger_disable(st->offload, st->offload_trigger); + + /* + * ad4695_exit_conversion_mode() triggers a conversion, so it has to be + * done after spi_offload_trigger_disable(). + */ + ret = ad4695_exit_conversion_mode(st); + if (ret) + return ret; + + ret = regmap_clear_bits(st->regmap, AD4695_REG_GP_MODE, + AD4695_REG_GP_MODE_BUSY_GP_EN); + if (ret) + return ret; + + spi_unoptimize_message(&st->buf_read_msg); + + return 0; +} + +static const struct iio_buffer_setup_ops ad4695_offload_buffer_setup_ops = { + .postenable = ad4695_offload_buffer_postenable, + .predisable = ad4695_offload_buffer_predisable, +}; + +/** + * ad4695_read_one_sample - Read a single sample using single-cycle mode + * @st: The AD4695 state + * @address: The address of the channel to read + * + * Upon successful return, the sample will be stored in `st->raw_data`. + * + * Context: can sleep, must be called with iio_device_claim_direct held + * Return: 0 on success, a negative error code on failure + */ +static int ad4695_read_one_sample(struct ad4695_state *st, unsigned int address) +{ + struct spi_transfer xfers[2] = { + { + .speed_hz = AD4695_REG_ACCESS_SCLK_HZ, + .bits_per_word = 16, + .tx_buf = &st->cnv_cmd, + .len = 2, + }, + { + /* Required delay between last SCLK and CNV/CS */ + .delay.value = AD4695_T_SCK_CNV_DELAY_NS, + .delay.unit = SPI_DELAY_UNIT_NSECS, + } + }; + int ret; + + ret = ad4695_set_single_cycle_mode(st, address); + if (ret) + return ret; + + /* + * If CNV is connected to CS, the previous function will have triggered + * the conversion, otherwise, we do it manually. + */ + if (st->cnv_gpio) + ad4695_cnv_manual_trigger(st); + + /* + * Setting the first channel to the temperature channel isn't supported + * in single-cycle mode, so we have to do an extra conversion to read + * the temperature. + */ + if (address == AD4695_CMD_TEMP_CHAN) { + st->cnv_cmd = AD4695_CMD_TEMP_CHAN << 11; + + ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers)); + if (ret) + return ret; + + /* + * If CNV is connected to CS, the previous function will have + * triggered the conversion, otherwise, we do it manually. + */ + if (st->cnv_gpio) + ad4695_cnv_manual_trigger(st); + } + + /* Then read the result and exit conversion mode. */ + st->cnv_cmd = AD4695_CMD_EXIT_CNV_MODE << 11; + xfers[0].rx_buf = &st->raw_data; + + return spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers)); +} + +static int __ad4695_read_info_raw(struct ad4695_state *st, + struct iio_chan_spec const *chan, + int *val) +{ + u8 realbits = chan->scan_type.realbits; + int ret; + + ret = ad4695_read_one_sample(st, chan->address); + if (ret) + return ret; + + if (chan->scan_type.sign == 's') + *val = sign_extend32(st->raw_data, realbits - 1); + else + *val = st->raw_data; + + return IIO_VAL_INT; +} + +static int ad4695_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct ad4695_state *st = iio_priv(indio_dev); + const struct iio_scan_type *scan_type; + struct ad4695_channel_config *cfg; + unsigned int reg_val; + int ret, tmp; + u8 realbits; + + if (chan->type == IIO_VOLTAGE) + cfg = &st->channels_cfg[chan->scan_index]; + + scan_type = iio_get_current_scan_type(indio_dev, chan); + if (IS_ERR(scan_type)) + return PTR_ERR(scan_type); + + realbits = scan_type->realbits; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + if (!iio_device_claim_direct(indio_dev)) + return -EBUSY; + + ret = __ad4695_read_info_raw(st, chan, val); + iio_device_release_direct(indio_dev); + return ret; + case IIO_CHAN_INFO_SCALE: + switch (chan->type) { + case IIO_VOLTAGE: + *val = st->vref_mv; + *val2 = realbits; + return IIO_VAL_FRACTIONAL_LOG2; + case IIO_TEMP: + /* T_scale (°C) = raw * V_REF (mV) / (-1.8 mV/°C * 2^16) */ + *val = st->vref_mv * -556; + *val2 = 16; + return IIO_VAL_FRACTIONAL_LOG2; + default: + return -EINVAL; + } + case IIO_CHAN_INFO_OFFSET: + switch (chan->type) { + case IIO_VOLTAGE: + if (cfg->pin_pairing == AD4695_IN_PAIR_COM) + *val = st->com_mv * (1 << realbits) / st->vref_mv; + else if (cfg->pin_pairing == AD4695_IN_PAIR_EVEN_ODD) + *val = cfg->common_mode_mv * (1 << realbits) / st->vref_mv; + else + *val = 0; + + return IIO_VAL_INT; + case IIO_TEMP: + /* T_offset (°C) = -725 mV / (-1.8 mV/°C) */ + /* T_offset (raw) = T_offset (°C) * (-1.8 mV/°C) * 2^16 / V_REF (mV) */ + *val = -47513600; + *val2 = st->vref_mv; + return IIO_VAL_FRACTIONAL; + default: + return -EINVAL; + } + case IIO_CHAN_INFO_CALIBSCALE: + switch (chan->type) { + case IIO_VOLTAGE: + if (!iio_device_claim_direct(indio_dev)) + return -EBUSY; + ret = regmap_read(st->regmap16, + AD4695_REG_GAIN_IN(chan->scan_index), + ®_val); + iio_device_release_direct(indio_dev); + if (ret) + return ret; + *val = reg_val; + *val2 = 15; + + return IIO_VAL_FRACTIONAL_LOG2; + default: + return -EINVAL; + } + case IIO_CHAN_INFO_CALIBBIAS: + switch (chan->type) + case IIO_VOLTAGE: { + if (!iio_device_claim_direct(indio_dev)) + return -EBUSY; + ret = regmap_read(st->regmap16, + AD4695_REG_OFFSET_IN(chan->scan_index), + ®_val); + iio_device_release_direct(indio_dev); + if (ret) + return ret; + + tmp = sign_extend32(reg_val, 15); + + switch (cfg->oversampling_ratio) { + case 1: + *val = tmp / 4; + *val2 = abs(tmp) % 4 * MICRO / 4; + break; + case 4: + *val = tmp / 2; + *val2 = abs(tmp) % 2 * MICRO / 2; + break; + case 16: + *val = tmp; + *val2 = 0; + break; + case 64: + *val = tmp * 2; + *val2 = 0; + break; + default: + return -EINVAL; + } + + if (tmp < 0 && *val2) { + *val *= -1; + *val2 *= -1; + } + + return IIO_VAL_INT_PLUS_MICRO; + default: + return -EINVAL; + } + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + switch (chan->type) { + case IIO_VOLTAGE: + *val = cfg->oversampling_ratio; + return IIO_VAL_INT; + default: + return -EINVAL; + } + case IIO_CHAN_INFO_SAMP_FREQ: { + struct pwm_state state; + unsigned int osr = 1; + + if (chan->type == IIO_VOLTAGE) + osr = cfg->oversampling_ratio; + + ret = pwm_get_state_hw(st->cnv_pwm, &state); + if (ret) + return ret; + + /* + * The effective sampling frequency for a channel is the input + * frequency divided by the channel's OSR value. + */ + *val = DIV_ROUND_UP_ULL(NSEC_PER_SEC, state.period * osr); + + return IIO_VAL_INT; + } + default: + return -EINVAL; + } +} + +static int ad4695_write_raw_get_fmt(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + long mask) +{ + switch (mask) { + case IIO_CHAN_INFO_SAMP_FREQ: + return IIO_VAL_INT; + default: + return IIO_VAL_INT_PLUS_MICRO; + } +} + +static int ad4695_set_osr_val(struct ad4695_state *st, + struct iio_chan_spec const *chan, + int val) +{ + int osr = ad4695_osr_to_regval(val); + + if (osr < 0) + return osr; + + switch (chan->type) { + case IIO_VOLTAGE: + st->channels_cfg[chan->scan_index].oversampling_ratio = val; + return regmap_update_bits(st->regmap, + AD4695_REG_CONFIG_IN(chan->scan_index), + AD4695_REG_CONFIG_IN_OSR_SET, + FIELD_PREP(AD4695_REG_CONFIG_IN_OSR_SET, osr)); + default: + return -EINVAL; + } +} + +static unsigned int ad4695_get_calibbias(int val, int val2, int osr) +{ + int val_calc, scale; + + switch (osr) { + case 4: + scale = 4; + break; + case 16: + scale = 2; + break; + case 64: + scale = 1; + break; + default: + scale = 8; + break; + } + + val = clamp_t(int, val, S32_MIN / 8, S32_MAX / 8); + + /* val2 range is (-MICRO, MICRO) if val == 0, otherwise [0, MICRO) */ + if (val < 0) + val_calc = val * scale - val2 * scale / MICRO; + else if (val2 < 0) + /* if val2 < 0 then val == 0 */ + val_calc = val2 * scale / (int)MICRO; + else + val_calc = val * scale + val2 * scale / MICRO; + + val_calc /= 2; + + return clamp_t(int, val_calc, S16_MIN, S16_MAX); +} + +static int __ad4695_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct ad4695_state *st = iio_priv(indio_dev); + unsigned int reg_val; + unsigned int osr = 1; + + if (chan->type == IIO_VOLTAGE) + osr = st->channels_cfg[chan->scan_index].oversampling_ratio; + + switch (mask) { + case IIO_CHAN_INFO_CALIBSCALE: + switch (chan->type) { + case IIO_VOLTAGE: + if (val < 0 || val2 < 0) + reg_val = 0; + else if (val > 1) + reg_val = U16_MAX; + else + reg_val = (val * (1 << 16) + + mul_u64_u32_div(val2, 1 << 16, + MICRO)) / 2; + + return regmap_write(st->regmap16, + AD4695_REG_GAIN_IN(chan->scan_index), + reg_val); + default: + return -EINVAL; + } + case IIO_CHAN_INFO_CALIBBIAS: + switch (chan->type) { + case IIO_VOLTAGE: + reg_val = ad4695_get_calibbias(val, val2, osr); + return regmap_write(st->regmap16, + AD4695_REG_OFFSET_IN(chan->scan_index), + reg_val); + default: + return -EINVAL; + } + case IIO_CHAN_INFO_SAMP_FREQ: { + struct pwm_state state; + /* + * Limit the maximum acceptable sample rate according to + * the channel's oversampling ratio. + */ + u64 max_osr_rate = DIV_ROUND_UP_ULL(st->chip_info->max_sample_rate, + osr); + + if (val <= 0 || val > max_osr_rate) + return -EINVAL; + + guard(mutex)(&st->cnv_pwm_lock); + pwm_get_state(st->cnv_pwm, &state); + /* + * The required sample frequency for a given OSR is the + * input frequency multiplied by it. + */ + state.period = DIV_ROUND_UP_ULL(NSEC_PER_SEC, val * osr); + return pwm_apply_might_sleep(st->cnv_pwm, &state); + } + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + return ad4695_set_osr_val(st, chan, val); + default: + return -EINVAL; + } +} + +static int ad4695_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + int ret; + + if (!iio_device_claim_direct(indio_dev)) + return -EBUSY; + ret = __ad4695_write_raw(indio_dev, chan, val, val2, mask); + iio_device_release_direct(indio_dev); + + return ret; +} + +static int ad4695_read_avail(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int **vals, int *type, int *length, + long mask) +{ + int ret; + static const int ad4695_calibscale_available[6] = { + /* Range of 0 (inclusive) to 2 (exclusive) */ + 0, 15, 1, 15, U16_MAX, 15 + }; + static const int ad4695_calibbias_available[4][6] = { + /* + * Datasheet says FSR/8 which translates to signed/4. The step + * depends on oversampling ratio, so we need four different + * ranges to select from. + */ + { + S16_MIN / 4, 0, + 0, MICRO / 4, + S16_MAX / 4, S16_MAX % 4 * MICRO / 4 + }, + { + S16_MIN / 2, 0, + 0, MICRO / 2, + S16_MAX / 2, S16_MAX % 2 * MICRO / 2, + }, + { + S16_MIN, 0, + 1, 0, + S16_MAX, 0, + }, + { + S16_MIN * 2, 0, + 2, 0, + S16_MAX * 2, 0, + }, + }; + struct ad4695_state *st = iio_priv(indio_dev); + unsigned int osr = 1; + + if (chan->type == IIO_VOLTAGE) + osr = st->channels_cfg[chan->scan_index].oversampling_ratio; + + switch (mask) { + case IIO_CHAN_INFO_CALIBSCALE: + switch (chan->type) { + case IIO_VOLTAGE: + *vals = ad4695_calibscale_available; + *type = IIO_VAL_FRACTIONAL_LOG2; + return IIO_AVAIL_RANGE; + default: + return -EINVAL; + } + case IIO_CHAN_INFO_CALIBBIAS: + switch (chan->type) { + case IIO_VOLTAGE: + ret = ad4695_osr_to_regval(osr); + if (ret < 0) + return ret; + /* + * Select the appropriate calibbias array based on the + * OSR value in the register. + */ + *vals = ad4695_calibbias_available[ret]; + *type = IIO_VAL_INT_PLUS_MICRO; + return IIO_AVAIL_RANGE; + default: + return -EINVAL; + } + case IIO_CHAN_INFO_SAMP_FREQ: + /* Max sample rate for the channel depends on OSR */ + st->sample_freq_range[2] = + DIV_ROUND_UP_ULL(st->chip_info->max_sample_rate, osr); + *vals = st->sample_freq_range; + *type = IIO_VAL_INT; + return IIO_AVAIL_RANGE; + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + switch (chan->type) { + case IIO_VOLTAGE: + *vals = ad4695_oversampling_ratios; + *length = ARRAY_SIZE(ad4695_oversampling_ratios); + *type = IIO_VAL_INT; + return IIO_AVAIL_LIST; + default: + return -EINVAL; + } + default: + return -EINVAL; + } +} + +static int ad4695_debugfs_reg_access(struct iio_dev *indio_dev, + unsigned int reg, + unsigned int writeval, + unsigned int *readval) +{ + struct ad4695_state *st = iio_priv(indio_dev); + int ret = -EINVAL; + + if (!iio_device_claim_direct(indio_dev)) + return -EBUSY; + + if (readval) { + if (regmap_check_range_table(st->regmap, reg, + &ad4695_regmap_rd_table)) + ret = regmap_read(st->regmap, reg, readval); + if (regmap_check_range_table(st->regmap16, reg, + &ad4695_regmap16_rd_table)) + ret = regmap_read(st->regmap16, reg, readval); + } else { + if (regmap_check_range_table(st->regmap, reg, + &ad4695_regmap_wr_table)) + ret = regmap_write(st->regmap, reg, writeval); + if (regmap_check_range_table(st->regmap16, reg, + &ad4695_regmap16_wr_table)) + ret = regmap_write(st->regmap16, reg, writeval); + } + iio_device_release_direct(indio_dev); + + return ret; +} + +static int ad4695_get_current_scan_type(const struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct ad4695_state *st = iio_priv(indio_dev); + unsigned int osr = st->channels_cfg[chan->scan_index].oversampling_ratio; + + switch (osr) { + case 1: + return AD4695_SCAN_TYPE_OSR_1; + case 4: + return AD4695_SCAN_TYPE_OSR_4; + case 16: + return AD4695_SCAN_TYPE_OSR_16; + case 64: + return AD4695_SCAN_TYPE_OSR_64; + default: + return -EINVAL; + } +} + +static const struct iio_info ad4695_info = { + .read_raw = &ad4695_read_raw, + .write_raw_get_fmt = &ad4695_write_raw_get_fmt, + .write_raw = &ad4695_write_raw, + .read_avail = &ad4695_read_avail, + .debugfs_reg_access = &ad4695_debugfs_reg_access, +}; + +static const struct iio_info ad4695_offload_info = { + .read_raw = &ad4695_read_raw, + .write_raw_get_fmt = &ad4695_write_raw_get_fmt, + .write_raw = &ad4695_write_raw, + .get_current_scan_type = &ad4695_get_current_scan_type, + .read_avail = &ad4695_read_avail, + .debugfs_reg_access = &ad4695_debugfs_reg_access, +}; + +static int ad4695_parse_channel_cfg(struct ad4695_state *st) +{ + struct device *dev = &st->spi->dev; + struct ad4695_channel_config *chan_cfg; + struct iio_chan_spec *iio_chan; + int ret, i; + + /* populate defaults */ + for (i = 0; i < st->chip_info->num_voltage_inputs; i++) { + chan_cfg = &st->channels_cfg[i]; + iio_chan = &st->iio_chan[i]; + + chan_cfg->highz_en = true; + chan_cfg->channel = i; + + /* This is the default OSR after reset */ + chan_cfg->oversampling_ratio = 1; + + *iio_chan = ad4695_channel_template; + iio_chan->channel = i; + iio_chan->scan_index = i; + iio_chan->address = AD4695_CMD_VOLTAGE_CHAN(i); + } + + /* modify based on firmware description */ + device_for_each_child_node_scoped(dev, child) { + u32 reg, val; + + ret = fwnode_property_read_u32(child, "reg", ®); + if (ret) + return dev_err_probe(dev, ret, + "failed to read reg property (%s)\n", + fwnode_get_name(child)); + + if (reg >= st->chip_info->num_voltage_inputs) + return dev_err_probe(dev, -EINVAL, + "reg out of range (%s)\n", + fwnode_get_name(child)); + + iio_chan = &st->iio_chan[reg]; + chan_cfg = &st->channels_cfg[reg]; + + chan_cfg->highz_en = + !fwnode_property_read_bool(child, "adi,no-high-z"); + chan_cfg->bipolar = fwnode_property_read_bool(child, "bipolar"); + + ret = fwnode_property_read_u32(child, "common-mode-channel", + &val); + if (ret && ret != -EINVAL) + return dev_err_probe(dev, ret, + "failed to read common-mode-channel (%s)\n", + fwnode_get_name(child)); + + if (ret == -EINVAL || val == AD4695_COMMON_MODE_REFGND) + chan_cfg->pin_pairing = AD4695_IN_PAIR_REFGND; + else if (val == AD4695_COMMON_MODE_COM) + chan_cfg->pin_pairing = AD4695_IN_PAIR_COM; + else + chan_cfg->pin_pairing = AD4695_IN_PAIR_EVEN_ODD; + + if (chan_cfg->pin_pairing == AD4695_IN_PAIR_EVEN_ODD && + val % 2 == 0) + return dev_err_probe(dev, -EINVAL, + "common-mode-channel must be odd number (%s)\n", + fwnode_get_name(child)); + + if (chan_cfg->pin_pairing == AD4695_IN_PAIR_EVEN_ODD && + val != reg + 1) + return dev_err_probe(dev, -EINVAL, + "common-mode-channel must be next consecutive channel (%s)\n", + fwnode_get_name(child)); + + if (chan_cfg->pin_pairing == AD4695_IN_PAIR_EVEN_ODD) { + char name[5]; + + snprintf(name, sizeof(name), "in%d", reg + 1); + + ret = devm_regulator_get_enable_read_voltage(dev, name); + if (ret < 0) + return dev_err_probe(dev, ret, + "failed to get %s voltage (%s)\n", + name, fwnode_get_name(child)); + + chan_cfg->common_mode_mv = ret / 1000; + } + + if (chan_cfg->bipolar && + chan_cfg->pin_pairing == AD4695_IN_PAIR_REFGND) + return dev_err_probe(dev, -EINVAL, + "bipolar mode is not available for inputs paired with REFGND (%s).\n", + fwnode_get_name(child)); + + if (chan_cfg->bipolar) + iio_chan->scan_type.sign = 's'; + + ret = ad4695_write_chn_cfg(st, chan_cfg); + if (ret) + return ret; + } + + /* Temperature channel must be next scan index after voltage channels. */ + st->iio_chan[i] = ad4695_temp_channel_template; + st->iio_chan[i].scan_index = i; + i++; + + st->iio_chan[i] = ad4695_soft_timestamp_channel_template; + st->iio_chan[i].scan_index = i; + + return 0; +} + +static bool ad4695_offload_trigger_match(struct spi_offload_trigger *trigger, + enum spi_offload_trigger_type type, + u64 *args, u32 nargs) +{ + if (type != SPI_OFFLOAD_TRIGGER_DATA_READY) + return false; + + /* + * Requires 2 args: + * args[0] is the trigger event. + * args[1] is the GPIO pin number. + */ + if (nargs != 2 || args[0] != AD4695_TRIGGER_EVENT_BUSY) + return false; + + return true; +} + +static int ad4695_offload_trigger_request(struct spi_offload_trigger *trigger, + enum spi_offload_trigger_type type, + u64 *args, u32 nargs) +{ + struct ad4695_state *st = spi_offload_trigger_get_priv(trigger); + + /* Should already be validated by match, but just in case. */ + if (nargs != 2) + return -EINVAL; + + /* DT tells us if BUSY event uses GP0 or GP3. */ + if (args[1] == AD4695_TRIGGER_PIN_GP3) + return regmap_set_bits(st->regmap, AD4695_REG_GP_MODE, + AD4695_REG_GP_MODE_BUSY_GP_SEL); + + return regmap_clear_bits(st->regmap, AD4695_REG_GP_MODE, + AD4695_REG_GP_MODE_BUSY_GP_SEL); +} + +static int +ad4695_offload_trigger_validate(struct spi_offload_trigger *trigger, + struct spi_offload_trigger_config *config) +{ + if (config->type != SPI_OFFLOAD_TRIGGER_DATA_READY) + return -EINVAL; + + return 0; +} + +/* + * NB: There are no enable/disable callbacks here due to requiring a SPI + * message to enable or disable the BUSY output on the ADC. + */ +static const struct spi_offload_trigger_ops ad4695_offload_trigger_ops = { + .match = ad4695_offload_trigger_match, + .request = ad4695_offload_trigger_request, + .validate = ad4695_offload_trigger_validate, +}; + +static void ad4695_pwm_disable(void *pwm) +{ + pwm_disable(pwm); +} + +static int ad4695_probe_spi_offload(struct iio_dev *indio_dev, + struct ad4695_state *st) +{ + struct device *dev = &st->spi->dev; + struct spi_offload_trigger_info trigger_info = { + .fwnode = dev_fwnode(dev), + .ops = &ad4695_offload_trigger_ops, + .priv = st, + }; + struct pwm_state pwm_state; + struct dma_chan *rx_dma; + int ret, i; + + indio_dev->info = &ad4695_offload_info; + indio_dev->num_channels = st->chip_info->num_voltage_inputs + 1; + indio_dev->setup_ops = &ad4695_offload_buffer_setup_ops; + + if (!st->cnv_gpio) + return dev_err_probe(dev, -ENODEV, + "CNV GPIO is required for SPI offload\n"); + + ret = devm_spi_offload_trigger_register(dev, &trigger_info); + if (ret) + return dev_err_probe(dev, ret, + "failed to register offload trigger\n"); + + st->offload_trigger = devm_spi_offload_trigger_get(dev, st->offload, + SPI_OFFLOAD_TRIGGER_DATA_READY); + if (IS_ERR(st->offload_trigger)) + return dev_err_probe(dev, PTR_ERR(st->offload_trigger), + "failed to get offload trigger\n"); + + ret = devm_mutex_init(dev, &st->cnv_pwm_lock); + if (ret) + return ret; + + st->cnv_pwm = devm_pwm_get(dev, NULL); + if (IS_ERR(st->cnv_pwm)) + return dev_err_probe(dev, PTR_ERR(st->cnv_pwm), + "failed to get CNV PWM\n"); + + pwm_init_state(st->cnv_pwm, &pwm_state); + + /* If firmware didn't provide default rate, use 10kHz (arbitrary). */ + if (pwm_state.period == 0) + pwm_state.period = 100 * MILLI; + + pwm_state.enabled = true; + + ret = pwm_apply_might_sleep(st->cnv_pwm, &pwm_state); + if (ret) + return dev_err_probe(dev, ret, "failed to apply CNV PWM\n"); + + ret = devm_add_action_or_reset(dev, ad4695_pwm_disable, st->cnv_pwm); + if (ret) + return ret; + + rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev, st->offload); + if (IS_ERR(rx_dma)) + return dev_err_probe(dev, PTR_ERR(rx_dma), + "failed to get offload RX DMA\n"); + + for (i = 0; i < indio_dev->num_channels; i++) { + struct iio_chan_spec *chan = &st->iio_chan[i]; + struct ad4695_channel_config *cfg; + + /* + * NB: When using offload support, all channels need to have the + * same bits_per_word because they all use the same SPI message + * for reading one sample. In order to prevent breaking + * userspace in the future when oversampling support is added, + * all channels are set read 19 bits with a shift of 3 to mask + * out the extra bits even though we currently only support 16 + * bit samples (oversampling ratio == 1). + */ + chan->scan_type.shift = 3; + chan->scan_type.storagebits = 32; + /* add sample frequency for PWM CNV trigger */ + chan->info_mask_separate |= BIT(IIO_CHAN_INFO_SAMP_FREQ); + chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_SAMP_FREQ); + + /* Add the oversampling properties only for voltage channels */ + if (chan->type != IIO_VOLTAGE) + continue; + + cfg = &st->channels_cfg[i]; + + chan->info_mask_separate |= BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO); + chan->info_mask_separate_available |= + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO); + chan->has_ext_scan_type = 1; + if (cfg->bipolar) { + chan->ext_scan_type = ad4695_scan_type_offload_s; + chan->num_ext_scan_type = + ARRAY_SIZE(ad4695_scan_type_offload_s); + } else { + chan->ext_scan_type = ad4695_scan_type_offload_u; + chan->num_ext_scan_type = + ARRAY_SIZE(ad4695_scan_type_offload_u); + } + } + + return devm_iio_dmaengine_buffer_setup_with_handle(dev, indio_dev, + rx_dma, IIO_BUFFER_DIRECTION_IN); +} + +static const struct spi_offload_config ad4695_spi_offload_config = { + .capability_flags = SPI_OFFLOAD_CAP_TRIGGER | + SPI_OFFLOAD_CAP_RX_STREAM_DMA, +}; + +static int ad4695_probe(struct spi_device *spi) +{ + struct device *dev = &spi->dev; + struct ad4695_state *st; + struct iio_dev *indio_dev; + bool use_internal_ldo_supply; + bool use_internal_ref_buffer; + int ret; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + st->spi = spi; + + st->chip_info = spi_get_device_match_data(spi); + if (!st->chip_info) + return -EINVAL; + + st->sample_freq_range[0] = 1; /* min */ + st->sample_freq_range[1] = 1; /* step */ + st->sample_freq_range[2] = st->chip_info->max_sample_rate; /* max */ + + st->regmap = devm_regmap_init(dev, &ad4695_regmap_bus, st, + &ad4695_regmap_config); + if (IS_ERR(st->regmap)) + return dev_err_probe(dev, PTR_ERR(st->regmap), + "Failed to initialize regmap\n"); + + st->regmap16 = devm_regmap_init(dev, &ad4695_regmap_bus, st, + &ad4695_regmap16_config); + if (IS_ERR(st->regmap16)) + return dev_err_probe(dev, PTR_ERR(st->regmap16), + "Failed to initialize regmap16\n"); + + st->cnv_gpio = devm_gpiod_get_optional(dev, "cnv", GPIOD_OUT_LOW); + if (IS_ERR(st->cnv_gpio)) + return dev_err_probe(dev, PTR_ERR(st->cnv_gpio), + "Failed to get CNV GPIO\n"); + + ret = devm_regulator_bulk_get_enable(dev, + ARRAY_SIZE(ad4695_power_supplies), + ad4695_power_supplies); + if (ret) + return dev_err_probe(dev, ret, + "Failed to enable power supplies\n"); + + /* If LDO_IN supply is present, then we are using internal LDO. */ + ret = devm_regulator_get_enable_optional(dev, "ldo-in"); + if (ret < 0 && ret != -ENODEV) + return dev_err_probe(dev, ret, + "Failed to enable LDO_IN supply\n"); + + use_internal_ldo_supply = ret == 0; + + if (!use_internal_ldo_supply) { + /* Otherwise we need an external VDD supply. */ + ret = devm_regulator_get_enable(dev, "vdd"); + if (ret < 0) + return dev_err_probe(dev, ret, + "Failed to enable VDD supply\n"); + } + + /* If REFIN supply is given, then we are using internal buffer */ + ret = devm_regulator_get_enable_read_voltage(dev, "refin"); + if (ret < 0 && ret != -ENODEV) + return dev_err_probe(dev, ret, "Failed to get REFIN voltage\n"); + + if (ret != -ENODEV) { + st->vref_mv = ret / 1000; + use_internal_ref_buffer = true; + } else { + /* Otherwise, we need an external reference. */ + ret = devm_regulator_get_enable_read_voltage(dev, "ref"); + if (ret < 0) + return dev_err_probe(dev, ret, + "Failed to get REF voltage\n"); + + st->vref_mv = ret / 1000; + use_internal_ref_buffer = false; + } + + ret = devm_regulator_get_enable_read_voltage(dev, "com"); + if (ret < 0 && ret != -ENODEV) + return dev_err_probe(dev, ret, "Failed to get COM voltage\n"); + + st->com_mv = ret == -ENODEV ? 0 : ret / 1000; + + /* + * Reset the device using hardware reset if available or fall back to + * software reset. + */ + + st->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(st->reset_gpio)) + return PTR_ERR(st->reset_gpio); + + if (st->reset_gpio) { + gpiod_set_value(st->reset_gpio, 0); + msleep(AD4695_T_WAKEUP_HW_MS); + } else { + ret = regmap_write(st->regmap, AD4695_REG_SPI_CONFIG_A, + AD4695_REG_SPI_CONFIG_A_SW_RST); + if (ret) + return ret; + + msleep(AD4695_T_WAKEUP_SW_MS); + } + + /* Needed for regmap16 to be able to work correctly. */ + ret = regmap_set_bits(st->regmap, AD4695_REG_SPI_CONFIG_A, + AD4695_REG_SPI_CONFIG_A_ADDR_DIR); + if (ret) + return ret; + + /* Disable internal LDO if it isn't needed. */ + ret = regmap_update_bits(st->regmap, AD4695_REG_SETUP, + AD4695_REG_SETUP_LDO_EN, + FIELD_PREP(AD4695_REG_SETUP_LDO_EN, + use_internal_ldo_supply ? 1 : 0)); + if (ret) + return ret; + + /* configure reference supply */ + + if (device_property_present(dev, "adi,no-ref-current-limit")) { + ret = regmap_set_bits(st->regmap, AD4695_REG_REF_CTRL, + AD4695_REG_REF_CTRL_OV_MODE); + if (ret) + return ret; + } + + if (device_property_present(dev, "adi,no-ref-high-z")) { + if (use_internal_ref_buffer) + return dev_err_probe(dev, -EINVAL, + "Cannot disable high-Z mode for internal reference buffer\n"); + + ret = regmap_clear_bits(st->regmap, AD4695_REG_REF_CTRL, + AD4695_REG_REF_CTRL_REFHIZ_EN); + if (ret) + return ret; + } + + ret = ad4695_set_ref_voltage(st, st->vref_mv); + if (ret) + return ret; + + if (use_internal_ref_buffer) { + ret = regmap_set_bits(st->regmap, AD4695_REG_REF_CTRL, + AD4695_REG_REF_CTRL_REFBUF_EN); + if (ret) + return ret; + + /* Give the capacitor some time to charge up. */ + msleep(AD4695_T_REFBUF_MS); + } + + ret = ad4695_parse_channel_cfg(st); + if (ret) + return ret; + + indio_dev->name = st->chip_info->name; + indio_dev->info = &ad4695_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = st->iio_chan; + indio_dev->num_channels = st->chip_info->num_voltage_inputs + 2; + + st->offload = devm_spi_offload_get(dev, spi, &ad4695_spi_offload_config); + ret = PTR_ERR_OR_ZERO(st->offload); + if (ret && ret != -ENODEV) + return dev_err_probe(dev, ret, "failed to get SPI offload\n"); + + /* If no SPI offload, fall back to low speed usage. */ + if (ret == -ENODEV) { + /* Driver currently requires CNV pin to be connected to SPI CS */ + if (st->cnv_gpio) + return dev_err_probe(dev, -EINVAL, + "CNV GPIO is not supported\n"); + + indio_dev->num_channels = st->chip_info->num_voltage_inputs + 2; + + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, + iio_pollfunc_store_time, + ad4695_trigger_handler, + &ad4695_buffer_setup_ops); + if (ret) + return ret; + } else { + ret = ad4695_probe_spi_offload(indio_dev, st); + if (ret) + return ret; + } + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct spi_device_id ad4695_spi_id_table[] = { + { .name = "ad4695", .driver_data = (kernel_ulong_t)&ad4695_chip_info }, + { .name = "ad4696", .driver_data = (kernel_ulong_t)&ad4696_chip_info }, + { .name = "ad4697", .driver_data = (kernel_ulong_t)&ad4697_chip_info }, + { .name = "ad4698", .driver_data = (kernel_ulong_t)&ad4698_chip_info }, + { } +}; +MODULE_DEVICE_TABLE(spi, ad4695_spi_id_table); + +static const struct of_device_id ad4695_of_match_table[] = { + { .compatible = "adi,ad4695", .data = &ad4695_chip_info, }, + { .compatible = "adi,ad4696", .data = &ad4696_chip_info, }, + { .compatible = "adi,ad4697", .data = &ad4697_chip_info, }, + { .compatible = "adi,ad4698", .data = &ad4698_chip_info, }, + { } +}; +MODULE_DEVICE_TABLE(of, ad4695_of_match_table); + +static struct spi_driver ad4695_driver = { + .driver = { + .name = "ad4695", + .of_match_table = ad4695_of_match_table, + }, + .probe = ad4695_probe, + .id_table = ad4695_spi_id_table, +}; +module_spi_driver(ad4695_driver); + +MODULE_AUTHOR("Ramona Gradinariu <ramona.gradinariu@analog.com>"); +MODULE_AUTHOR("David Lechner <dlechner@baylibre.com>"); +MODULE_DESCRIPTION("Analog Devices AD4695 ADC driver"); +MODULE_LICENSE("GPL"); +MODULE_IMPORT_NS("IIO_DMAENGINE_BUFFER"); |